Preheat a ridged cast iron griddle. Slice the potatoes in half and brush the cut side with the olive oil. Grill the potatoes for a few minutes and transfer to a serving platter. Finely slice the spirng onion and scatter these along with the walnuts on top of the potatoes. In a small bowl combine the walnut oil and vinegar along with some salt and pepper and then dress the potatoes with this. Posted to Digest bread-bakers.v097.n,